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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2014 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: ApplyExprFunction.html 842 2015-03-07 18:20:42Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.jsimpledb.parse.func;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import org.jsimpledb.parse.ParseContext;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import org.jsimpledb.parse.ParseException;<a name="line.11"></a>
<span class="sourceLineNo">012</span>import org.jsimpledb.parse.ParseSession;<a name="line.12"></a>
<span class="sourceLineNo">013</span>import org.jsimpledb.parse.expr.AtomParser;<a name="line.13"></a>
<span class="sourceLineNo">014</span>import org.jsimpledb.parse.expr.ExprParser;<a name="line.14"></a>
<span class="sourceLineNo">015</span>import org.jsimpledb.parse.expr.Node;<a name="line.15"></a>
<span class="sourceLineNo">016</span>import org.jsimpledb.parse.expr.Value;<a name="line.16"></a>
<span class="sourceLineNo">017</span>import org.jsimpledb.parse.expr.VarNode;<a name="line.17"></a>
<span class="sourceLineNo">018</span><a name="line.18"></a>
<span class="sourceLineNo">019</span>public abstract class ApplyExprFunction extends AbstractFunction {<a name="line.19"></a>
<span class="sourceLineNo">020</span><a name="line.20"></a>
<span class="sourceLineNo">021</span>    protected ApplyExprFunction(String name) {<a name="line.21"></a>
<span class="sourceLineNo">022</span>        super(name);<a name="line.22"></a>
<span class="sourceLineNo">023</span>    }<a name="line.23"></a>
<span class="sourceLineNo">024</span><a name="line.24"></a>
<span class="sourceLineNo">025</span>    @Override<a name="line.25"></a>
<span class="sourceLineNo">026</span>    public ParamInfo parseParams(ParseSession session, ParseContext ctx, boolean complete) {<a name="line.26"></a>
<span class="sourceLineNo">027</span><a name="line.27"></a>
<span class="sourceLineNo">028</span>        // Get items<a name="line.28"></a>
<span class="sourceLineNo">029</span>        final int mark = ctx.getIndex();<a name="line.29"></a>
<span class="sourceLineNo">030</span>        if (ctx.tryLiteral(")"))<a name="line.30"></a>
<span class="sourceLineNo">031</span>            throw new ParseException(ctx, "three parameters required for " + this.name + "()");<a name="line.31"></a>
<span class="sourceLineNo">032</span>        final Node items = new ExprParser().parse(session, ctx, complete);<a name="line.32"></a>
<span class="sourceLineNo">033</span><a name="line.33"></a>
<span class="sourceLineNo">034</span>        // Get variable<a name="line.34"></a>
<span class="sourceLineNo">035</span>        ctx.skipWhitespace();<a name="line.35"></a>
<span class="sourceLineNo">036</span>        if (!ctx.tryLiteral(","))<a name="line.36"></a>
<span class="sourceLineNo">037</span>            throw new ParseException(ctx, "expected `,'").addCompletion(", ");<a name="line.37"></a>
<span class="sourceLineNo">038</span>        this.spaceParser.parse(ctx, complete);<a name="line.38"></a>
<span class="sourceLineNo">039</span>        final Node param1 = new AtomParser().parse(session, ctx, complete);<a name="line.39"></a>
<span class="sourceLineNo">040</span>        if (!(param1 instanceof VarNode)) {<a name="line.40"></a>
<span class="sourceLineNo">041</span>            ctx.setIndex(mark);<a name="line.41"></a>
<span class="sourceLineNo">042</span>            throw new ParseException(ctx, "expected variable as second parameter to " + this.name + "()");<a name="line.42"></a>
<span class="sourceLineNo">043</span>        }<a name="line.43"></a>
<span class="sourceLineNo">044</span>        final String variable = ((VarNode)param1).getName();<a name="line.44"></a>
<span class="sourceLineNo">045</span><a name="line.45"></a>
<span class="sourceLineNo">046</span>        // Get expression<a name="line.46"></a>
<span class="sourceLineNo">047</span>        ctx.skipWhitespace();<a name="line.47"></a>
<span class="sourceLineNo">048</span>        if (!ctx.tryLiteral(","))<a name="line.48"></a>
<span class="sourceLineNo">049</span>            throw new ParseException(ctx, "expected `,'").addCompletion(", ");<a name="line.49"></a>
<span class="sourceLineNo">050</span>        this.spaceParser.parse(ctx, complete);<a name="line.50"></a>
<span class="sourceLineNo">051</span>        final Node expr = new ExprParser().parse(session, ctx, complete);<a name="line.51"></a>
<span class="sourceLineNo">052</span><a name="line.52"></a>
<span class="sourceLineNo">053</span>        // Finish parse<a name="line.53"></a>
<span class="sourceLineNo">054</span>        ctx.skipWhitespace();<a name="line.54"></a>
<span class="sourceLineNo">055</span>        if (!ctx.tryLiteral(")"))<a name="line.55"></a>
<span class="sourceLineNo">056</span>            throw new ParseException(ctx, "expected `)'").addCompletion(") ");<a name="line.56"></a>
<span class="sourceLineNo">057</span><a name="line.57"></a>
<span class="sourceLineNo">058</span>        // Done<a name="line.58"></a>
<span class="sourceLineNo">059</span>        return new ParamInfo(variable, items, expr);<a name="line.59"></a>
<span class="sourceLineNo">060</span>    }<a name="line.60"></a>
<span class="sourceLineNo">061</span><a name="line.61"></a>
<span class="sourceLineNo">062</span>    @Override<a name="line.62"></a>
<span class="sourceLineNo">063</span>    public final Value apply(ParseSession session, Object params) {<a name="line.63"></a>
<span class="sourceLineNo">064</span>        return this.apply(session, (ParamInfo)params);<a name="line.64"></a>
<span class="sourceLineNo">065</span>    }<a name="line.65"></a>
<span class="sourceLineNo">066</span><a name="line.66"></a>
<span class="sourceLineNo">067</span>    /**<a name="line.67"></a>
<span class="sourceLineNo">068</span>     * Apply this function.<a name="line.68"></a>
<span class="sourceLineNo">069</span>     *<a name="line.69"></a>
<span class="sourceLineNo">070</span>     * @param session parse session<a name="line.70"></a>
<span class="sourceLineNo">071</span>     * @param params function parameters<a name="line.71"></a>
<span class="sourceLineNo">072</span>     * @return the value of this function<a name="line.72"></a>
<span class="sourceLineNo">073</span>     */<a name="line.73"></a>
<span class="sourceLineNo">074</span>    protected abstract Value apply(ParseSession session, ParamInfo params);<a name="line.74"></a>
<span class="sourceLineNo">075</span><a name="line.75"></a>
<span class="sourceLineNo">076</span>    /**<a name="line.76"></a>
<span class="sourceLineNo">077</span>     * Set the variable to the given value and then evaluate the expression.<a name="line.77"></a>
<span class="sourceLineNo">078</span>     * Any previous value of the variable is saved prior and restored after.<a name="line.78"></a>
<span class="sourceLineNo">079</span>     *<a name="line.79"></a>
<span class="sourceLineNo">080</span>     * @param session parse session<a name="line.80"></a>
<span class="sourceLineNo">081</span>     * @param variable the name of the variable to use<a name="line.81"></a>
<span class="sourceLineNo">082</span>     * @param value the value to set to the variable<a name="line.82"></a>
<span class="sourceLineNo">083</span>     * @param expr the expression to evaluate<a name="line.83"></a>
<span class="sourceLineNo">084</span>     * @return the value of the expression<a name="line.84"></a>
<span class="sourceLineNo">085</span>     */<a name="line.85"></a>
<span class="sourceLineNo">086</span>    protected Value evaluate(ParseSession session, String variable, Value value, Node expr) {<a name="line.86"></a>
<span class="sourceLineNo">087</span><a name="line.87"></a>
<span class="sourceLineNo">088</span>        // Save previous variable value, if any<a name="line.88"></a>
<span class="sourceLineNo">089</span>        final boolean hasPreviousValue = session.getVars().containsKey(variable);<a name="line.89"></a>
<span class="sourceLineNo">090</span>        final Value previousValue = hasPreviousValue ? session.getVars().get(variable) : null;<a name="line.90"></a>
<span class="sourceLineNo">091</span><a name="line.91"></a>
<span class="sourceLineNo">092</span>        // Assign variable<a name="line.92"></a>
<span class="sourceLineNo">093</span>        session.getVars().put(variable, value);<a name="line.93"></a>
<span class="sourceLineNo">094</span>        final Value result;<a name="line.94"></a>
<span class="sourceLineNo">095</span>        try {<a name="line.95"></a>
<span class="sourceLineNo">096</span><a name="line.96"></a>
<span class="sourceLineNo">097</span>            // Evaluate expression<a name="line.97"></a>
<span class="sourceLineNo">098</span>            result = expr.evaluate(session);<a name="line.98"></a>
<span class="sourceLineNo">099</span><a name="line.99"></a>
<span class="sourceLineNo">100</span>        } finally {<a name="line.100"></a>
<span class="sourceLineNo">101</span><a name="line.101"></a>
<span class="sourceLineNo">102</span>            // Restore previous variable value<a name="line.102"></a>
<span class="sourceLineNo">103</span>            if (hasPreviousValue)<a name="line.103"></a>
<span class="sourceLineNo">104</span>                session.getVars().put(variable, previousValue);<a name="line.104"></a>
<span class="sourceLineNo">105</span>        }<a name="line.105"></a>
<span class="sourceLineNo">106</span><a name="line.106"></a>
<span class="sourceLineNo">107</span>        // Done<a name="line.107"></a>
<span class="sourceLineNo">108</span>        return result;<a name="line.108"></a>
<span class="sourceLineNo">109</span>    }<a name="line.109"></a>
<span class="sourceLineNo">110</span><a name="line.110"></a>
<span class="sourceLineNo">111</span>// ParamInfo<a name="line.111"></a>
<span class="sourceLineNo">112</span><a name="line.112"></a>
<span class="sourceLineNo">113</span>    static class ParamInfo {<a name="line.113"></a>
<span class="sourceLineNo">114</span><a name="line.114"></a>
<span class="sourceLineNo">115</span>        private final String variable;<a name="line.115"></a>
<span class="sourceLineNo">116</span>        private final Node items;<a name="line.116"></a>
<span class="sourceLineNo">117</span>        private final Node expr;<a name="line.117"></a>
<span class="sourceLineNo">118</span><a name="line.118"></a>
<span class="sourceLineNo">119</span>        ParamInfo(String variable, Node items, Node expr) {<a name="line.119"></a>
<span class="sourceLineNo">120</span>            this.variable = variable;<a name="line.120"></a>
<span class="sourceLineNo">121</span>            this.items = items;<a name="line.121"></a>
<span class="sourceLineNo">122</span>            this.expr = expr;<a name="line.122"></a>
<span class="sourceLineNo">123</span>        }<a name="line.123"></a>
<span class="sourceLineNo">124</span><a name="line.124"></a>
<span class="sourceLineNo">125</span>        public String getVariable() {<a name="line.125"></a>
<span class="sourceLineNo">126</span>            return this.variable;<a name="line.126"></a>
<span class="sourceLineNo">127</span>        }<a name="line.127"></a>
<span class="sourceLineNo">128</span><a name="line.128"></a>
<span class="sourceLineNo">129</span>        public Node getItems() {<a name="line.129"></a>
<span class="sourceLineNo">130</span>            return this.items;<a name="line.130"></a>
<span class="sourceLineNo">131</span>        }<a name="line.131"></a>
<span class="sourceLineNo">132</span><a name="line.132"></a>
<span class="sourceLineNo">133</span>        public Node getExpr() {<a name="line.133"></a>
<span class="sourceLineNo">134</span>            return this.expr;<a name="line.134"></a>
<span class="sourceLineNo">135</span>        }<a name="line.135"></a>
<span class="sourceLineNo">136</span>    }<a name="line.136"></a>
<span class="sourceLineNo">137</span>}<a name="line.137"></a>
<span class="sourceLineNo">138</span><a name="line.138"></a>




























































</pre>
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